A variety of styles of packer have been used downhole for isolation. In some applications there is a need to run various conduits or lines past a packer. In the past the packer mandrels have been provided with a passage and end connections at opposed ends which required connections to be made at the surface before running the packer into the wellbore. The problem of connections was more severe in some applications than others. For example if the line was a hydraulic control line, then the connections posed a potential for leakage. If the line was a fiber optic then ensuring a clean connection at a splice was a significant issue.
One attempt to deal with control lines in a packer environment involving pipe expansion is illustrated in FIGS. 2, 40 and 42 of the following related US applications: 20080251250; 20070267201; 20070114044; 20070114019; 20070114018; 20070114017 and 20070114016. In these references rubber rings are secured outside a tubular. The rings have bores through which the control lines extend. The assembly is expanded from within the tubular to seal within a wellbore and to protect the control lines from damage. Swelling is not used in these references while some embodiments also include inflatable concepts.
Swelling packers respond to well fluids or introduced fluids to grow larger and seal in a wellbore. Covers or other time delay techniques have been used to allow time to run in the packer to the desired depth before it swells into a sealing relationship with a surrounding tubular or the open hole. In these applications a longitudinal channel for control lines in the swelling element have been provided that extends between opposed ends with the idea being that such a trough will close up when swelling occurs. This feature is in a Swellpacker® Cable System sold by Halliburton. The sealing reliability of such a design, however, depended on a fairly symmetrical borehole and a swelling closed of an open trough over the control line for the length of the sealing element, which did not always occur.
The present invention addresses the shortcomings in the Halliburton packer in an effort to enhance the integrity of the seal once swelling has occurred. In one embodiment a swelling element has a milled slot with a longitudinal cut extending through the slot that goes between opposed ends of the element. The control line or conduit is first wrapped in an underlayment that is rubber that does not swell. The ends can overlap each other in a scroll fashion or can be otherwise joined together. An outer tube that can be longitudinally or spirally split is put over the control line underlayment. The underlayment and its outer cover fit into the elongated slot in the swelling element. If the slot in the outer tube for the control line or conduit has a longitudinal split, the split is rotated to not show in the elongated slot of packer sealing element. Other embodiments are envisioned and described below. Those skilled in the art will better understand some of the embodiments of the invention from the description below and the associated figures while appreciating that the full scope of the invention is to be found in the appended claims.